For vertical breakdown near to an under construction building establish the working reference point which mark define from the nearest reference points state nivelirnoj networks.
In building heights from a conditional zero mark - level of a floor of the ground floor often reckon, thus in the project specify an absolute mark (i.e. From a sea level) a zero mark.
We Will consider on an example as it do. We will admit that level of a zero mark needs to be fixed on obnoske (fig. 113. The absolute mark of a zero point under the project is equal 102,285, and a reference point mark - 104,012. Hence, level of a zero mark below reference point level on 1,727м. To transfer a zero mark in a column 4 old clothes, between it and a reference point place a level 3, on a reference point put rejku 2 and do by a level readout. We will assume that readout on rejke is equal 525мм. Then the mark of horizon of the tool will be 104,012+0,525=104,537. Then calculate a difference between a mark of horizon of the tool and an absolute mark of a zero point: 104,537 - 102,285=2,252м. Readout on rejke, established on a zero mark should give this difference. Vising on rejku, it is established at a column by old clothes so that readout on rejke was 2252мм. Having received this readout, on the bottom end rejki on a column old clothes draw a line which serves as level of a zero mark. For fastening of this level on a column old clothes hammer in the probe or a nail.
At vertical breakdown of buildings from a zero mark conduct all readout downwards and upwards. Marks above conditional level have a plus, more low - a minus. For example, the floor of the second floor of an apartment house will be on a mark plus 3,000, and an input in the house - a minus 0,850.
From a zero mark it is possible to execute easily vertical breakdown of a bottom of a foundation ditch (fig. 113, a sawn-off shotgun of the base, window and doorways, interfloor overlappings, eaves. For this purpose use the design marks specified on drawings of vertical cuts of a building.
a Fig. 113. Crossing of marks by a level :
And - on obnosku, - in a foundation ditch;
1 - a reference point, 2 - rejka, 3 - a level, 4 - a column old clothes, а1, a2 - readout on rejkam, в1, в2 - tool horizon